Tips to install your metal roof tiles right
Metal roofing tile materials like steel, zinc and copper rarely require maintenance and help ensure a metal roof’s longevity. That is, provided they are installed correctly. Errors in metal roof tile installation can result in frustration, delays, leaks and costly repairs. What follows are common metal roof tile installation errors and their remedies.
Getting Ready for the Roof
Khary Penebaker, president, Roofed Right America LLC, Milwaukee, says to avoid metal tile (or any type of roof) roof installation errors, start with effective planning and preparation. “Inadequate planning can cause a reduction in installation efficiency, which reduces or can eliminate profitability,” he says. “If the crew doesn’t know how to load the roof properly, they could cause a failure in the deck due to excess weight loads or they can very easily create a very unsafe work environment. Their safety lines-provided that they use them, which they should-could get tangled up with the material because of material spacing. Also, I believe it is always better to include the roofing manufacturer with the ventilation manufacturer, if they are separate, in the design phase of the project so that everyone is on the same page. This also provides additional sets of eyes that can provide a different perspective on their respective approaches as well as providing additional expert advice and recommendations.”
To ensure error-free metal tile installation, take advantage of manufacturers’ product training. Learn preferred installation methods and more importantly, follow them. Most manufacturers offer job-site training, regional training and even technicians available via telephone.
“If you have any questions, call the manufacturer to speak with them, and review certain details and questions prior to starting your job,” say regional and installation managers at Corona, Calif.-based DECRA Roofing Systems Inc. “A quality manufacturer will have all of these resources available to the contractor to ensure their job runs smooth. Manufacturer installation guide review and understanding are the first steps to avoiding installation errors such as improper notching, bending, penetrations and flashing details.”
Penebaker agrees, saying, “The more trained contractors are, the better and safer their jobs will be. I am a firm believer in getting manufacturer-sponsored training in addition to having contractors obtain certified status from the various manufacturers.” Also, building codes, industry standards, local jurisdictions and established protocol provide prescriptive requirements and guidelines for correct installation.
Slope and Shape
To avoid errors, confirm the roof pitch is conducive to the material being used. Errors can occur when installing metal tiles on roof slopes less than 3:12, especially when installing zinc tiles. “The most common error I see is products being installed at less than their minimum required pitch,” says Todd Miller, president, Isaiah Industries Inc., Piqua Ohio. “Products that have horizontal laps will often have a 3:12 minimum pitch. Going below that pitch will cause problems.”
The overall condition of the roof should be assessed to confirm a solid base. To prevent installation errors, most metal roofing products require solid decking. Check for dry rot and other signs of water damage on the roof deck before metal roof tile installation. For new roofs, the deck should be inspected to determine a level plain has been installed. For a re-roof, the existing deck and roofing materials should be closely inspected to determine if the surface is adequate to receive the new tiles or if deck repairs should be performed. In either case, the new or existing deck should be checked for squareness and shape.
“The roof’s shape may dictate the type of system (along with the building’s use); however, there may be conditions that will fail if the wrong system is used or at least the wrong detail flashings are used that can cause overall system failure,” Penebaker says.
Roofs shaped with “closed valley systems” are designed to carry water beneath the metal roofing tile. “Those valleys are prone to collecting debris and then plugging up,” Miller says. “Also, when it comes to flashings, installers must make sure that their flashings always maintain a positive pitch for proper water flow down the roof. The thickness of the metal shingles can sometimes cause improperly placed flashings to not maintain positive pitch. It sounds way too simple but it’s so critical to remember that water flows downhill. Make sure that all flashings are lapped accordingly. Additionally, make sure that underlayments are brought up around penetrations and down over the roof edges. This helps provide greater protection.”
Underlayment Errors
Protect the underside of the metal roof tiles with an underlayment that has a smooth, non-granulated, high-temperature surface. “Metal generates more heat than asphalt shingles and needs to be installed over a high-temperature underlayment designed to handle these increased heating conditions,” says Brian Short, business unit manager, Atlas Roofing Corp., Atlanta. “Make sure to use an underlayment that has a durable facing that holds up under normal foot traffic during the installation process. Our WeatherMaster Polyseal SE is manufactured using a polyester facing that is durable under high foot traffic. It allows for a direct-to-deck installation. The facing will not scratch the back of the metal roofing which would cause rust and ultimately leaks in the final roof covering.” Loading and setting the roof up correctly will minimize the damage to the underlayment. Not strategically stacking the metal tiles over the roof can cause potential underlayment damage. It can also create an unsafe work environment and berth an inefficient start to the roof project.
“Contractors can place plywood over exposed underlayment to protect it from tear off debris, when engaging in roof removals,” Penebaker says. “Ladders should also have insulation on the backside (the side touching the roof, if using roof ladders) so that ladder placement and movement don’t scratch the underlayment. Contractors should also make sure that they don’t overdrive nails that reduce the fastening pressure from the nails or caps. They should also make sure the underlayment isn’t too loose so that fasteners or staples don’t blow through the underlayment, which definitely cause blow offs.”
The Right Equipment
A contractor can’t successfully install metal roof tiles without the right equipment. “A metal tile roof may require a drill rather than a hammer, so without the drill the roofer can’t install the tile at all or correctly,” says Penebaker. “Without a tape measure, the roofer can’t layout the roof properly either, which could and will lead to system failure down the line. Metal tile roofs will require shears, saws (maybe) and/or a guillotine for cutting, so a roofer can’t bring just a utility knife! The system will most likely require the use of a hand break, so without a pair of those on the job, the fl ashings won’t be terminated properly. It is all in the preparation.”
Joe Stager, vice president of product development and marketing at Triangle Fastener Corp., Pittsburgh, contends that one specific way to ensure error-free metal roof tile installation focuses on the screw used for attachment. “Installing the screw perpendicular to the metal surface is critical,” he says. “This will help the screw to penetrate the steel and substrate with less effort. It is important to tighten the screw to secure the panel correctly. Over tightening can strip out the screw, which can cause fastener backout and decrease the pullout strength. Use a screw gun that has a depth-sensing or torque-control feature to ensure proper installation.”
Most projects involving metal shingles and tiles will require a portable handbrake to be on the job. “An 8- or 10-foot brake is great for longer flashings being bent on the ground,” Miller says. “Many installers will also have a 2- or 3-foot brake that they take up on the roof with them. Using a good brake will help ensure that flashing has precise, crisp bends. That makes the jobs look right and perform very well.”
DECRA Roofing Systems’ regional and installation managers stress that following manufacturer instructions and recommendations on roofing tools will go a long way to reduce installation errors and accelerate application times. “Contractors should also consider specific manufacturers with proven systems that simplify installation techniques and do not require specialized installation tools,” the DECRA managers say. “DECRA’s Direct to Deck-Cut and Tuck Profiles/Systems, require nothing more than everyday tools such as tin snips, a circular saw and cordless drill. Some manufacturers only offer profi les that require investing in specialized tools to cut, fold and bend panels and accessories. If not properly educated, many contractors improvise rather than investing in the recommended tools resulting in higher labor costs, frustration, poor workmanship and a greater potential for installation issues.”
Sidebar: A Contractor’s Competency and Capability
Yes, obvious mistakes can occur with metal roof tile installation. Contractors who may be anxious to sell a job may not consider their own capacity or their sub’s capacity, then they go to the job and butcher it! I believe that contractors shouldn’t sell roof systems that they aren’t familiar with. Ultimately, before a customer receives a proposal, the contractor should definitely make sure they are fully aware and capable of installing the proposed roof system. If the contractor doesn’t know what they are doing, it will definitely show in the system as well as with future failures. A contractor is better off declining the opportunity than taking a job with a system they are unfamiliar with. If you can’t swim, don’t jump in the water!
Khary Penebaker, president, Roofed Right America LLC, Milwaukee 
